Fuel feed devices for internal combustion engines

ABSTRACT

The fuel feed device includes a fuel injector controlled by an electromagnetic valve. A metering system has a rotary member adapted to send an energizing signal into the electromagnet during a fraction of each turn of the member. A signal generator is adapted to employ, on each turn of the rotary member, a release signal which lasts during a predetermined and constant fraction of a turn of the rotary member to produce the energizing signal whose duration varies in the same sense as that of the release signal and in the same sense as the degree of opening of an auxiliary throttle member in the intake pipe upstream of the main throttle. The auxiliary throttle opens automatically and progressively in proportion as the flow of air increases. The signal generator may comprise a threshold sensing device for the charge on a condenser fed by switch means controlled by the rotary member. The signal generator may comprise a computing device operated by pulses controlled by the rotary member.

Unite States Patent 1 1 1111 3,867,913 Pierlot Feb. 25, 1975 FUEL FEEDDEVICES FOR INTERNAL 3,482,558 12/1969 Casey et al 123/139 AW COMBUSTIONENGINES 3,543,739 12/1970 Mennesson 1. 123/119 3,575,147 4/1971 Harrison123/32 EA [75] Inventor: Michel Eugene Pierlot, Le Peco,

France [73] Assignee: Societe Industrielle De Brevets Et DEtudesS.l.B.E., Neuilly-sur-Seine, France [22] Filed: Apr. 3, 1972 [21] Appl.No.: 240,767

Related US. Application Data [63] Continuation of Ser. No. 10,420, Feb.11, 1970,

abandoned.

[30] Foreign Application Priority Data Feb. 14, 1969 France 69.03791Apr. 28, 1969 France 69.13514 [52] US. Cl... 123/32 EA, 123/139 AW,123/119 R [51] Int. Cl. F021) 3/00, F02m 39/00 [58] Field of Search123/32, 119 R, 139 AW [56] References Cited UNITED STATES PATENTS2,856,910 10/1958 Goodridge 123/32 AE 3,000,368 9/1961 Knapp et al.123/32 EA 3,006,329 10/1961 Armstrong 123/139 AW 3,430,616 3/1969Glockler et al 123/32 EA Primary Examiner-Charles J. Myhre AssistantExaminer-Ronald B. Cox Attorney, Agent, or FirmFleit & Jacobson [57]ABSTRACT The fuel feed device includes a fuel injector controlled by anelectromagnetic valve. A metering system has a rotary member adapted tosend an energizing signal into the electromagnet during a fraction ofeach turn of the member. A signal generator is adapted to employ, oneach turn of the rotary member, a release signal which lasts during apredetermined and constant fraction of a turn of the rotary member toproduce the energizing signal whose duration varies in the same sense asthat of the release signal and in the same sense as the degree ofopening of an auxiliary throttle member in the intake pipe upstream ofthe main throttle. The auxiliary throttle opens automatically andprogressively in proportion as the flow of air increases. The signalgenerator may comprise a threshold sensing device for the charge on acondenser fed by switch means controlled by the rotary member. Thesignal generator may comprise a computing device operated by pulsescontrolled by the rotary member.

15 Claims, 7 Drawing Figures PATENTED FEB2 5 ms sum 1 [IF 5 INVENTORMichal E. Pier/oi:

ATTORNE5 PATENTED FEBRSIGT? SHEET 0F 6 FUEL FEED DEVECES FOR HNTEIRNALCOMBUSTION ENGINES This is a continuation of application Ser. No.10,420, filed Feb. 11, 1970, now abandoned.

The present invention relates to fuel feed devices, for internalcombustion engines, of the type comprising, on one hand, in their intakepipe, a main throttle member actuated by the driver, on the other hand,a source of fuel under pressure, whose delivery circuit, which opensinto the portion of the intake pipe situated downstream of the mainthrottle member, is controlled by at least one valve actuated by anelectromagnet and, on the other hand finally, a metering system which,provided with a rotary member driven in continuous rotation, is adaptedto send into this electromagnet at least one energising signal during afraction of each turn of the said rotary member which is regulated bythis systern.

It is known that the regulation of this fraction of a turn determines,in a given interval of time, the total duration of opening of the valveand, consequently, the

flow of fuel injected in the intake pipe during the said interval oftime.

Feed devices are known (such as those described in British patentapplication No. 48,076/68 filed Oct. 10, 1968 in which the adjustment ofthis fraction of a turn is obtained by mechanical means controlled by amember sensitive to the flow of air in said pipe, that is to say to theflow of air by weight per unit time consumed by the engine.

However these devices are relatively bulky and impose on the whole ofthe rotary member, the member sensitive to the flow of air and themechanical means which connect them, a volume and a positioning oftendifficult to ensure in practice.

It is a particular object of the invention to overcome theabove-mentioned drawbacks and to render these feed devices such thatthey comply better than up to the present to the various desiderata ofpractice.

To this end, the feed device according to the invention comprises asignal generator adapted to employ, on each turn of said rotary member,a release signal which lasts during a predetermined and constantfraction of a turn of said rotary member, to produce an energisingsignal whose duration varies in the same sense as that of the releasesignal and in the same sense as the degree of opening of an auxiliarythrottle member which is arranged in the intake pipe upstream of themain throttle member and which is arranged to be opened automaticallyand progressively in proportion as the flow of air in said pipeincreases, the assembly being such that the fraction of each turn ofsaid rotary member during which the energising signal is sent into theelectromagnet varies in the same sense as the degree of opening of theauxiliary throttle member.

This signal generator may be constituted in numerous ways by making itcomprise for example an element, preferably of variable impedance,sensitive to the position of the said auxiliary throttle member andhaving an influence on the duration of the energising signals suppliedby the signal generator.

In a preferred embodiment, the said signal generator comprises acondenser, a variable resistance or rh'eostat and switch means adaptedto actuate successively, and on each turn of the rotary member, thecharge of the said condenser during the rotation of a predeterminedangle of this rotary member and the discharge of this condenser into acircuit constituted by the variable resistance and by a threshold deviceconnected in series, the threshold device sending; into theelectromagnet an energising signal as long as the discharge current isgreater than a given threshold.

The switch means have advantageously two stable states, a first statecorresponding to the charging of the condenser and a second statecorresponding to the discharge of the said condenser, these means beingactuated by a signal furnished by a field sensor in the neighbourhood ofwhich is rotated a magnetic mass rigidly fixed to the said rotarymember, a rotation through a predetermined angle of the magnetic massgenerating in the sensor, on each turn of this rotary member, a releasesignal of which the beginning actuates the placing into the first stateof the said switch means and of which the end actuates the placing intothe second state of the said switch means.

Variable resistance is advantageously constituted by a rheostat providedwith a movable slider whose displacements are actuated by the movementsof a cam which is rigidly fixed to the auxiliary throttling member andwhich comprises an active surface bearing on a mechanical connectingmember movable with the said slider.

According to another feature of the invention, the feed device is,mainly, characterized by the fact that the above-said signal generatorcomprises a computing device adapted to supply the said energisingsignal from,, on one hand, a first siognall which represents the measureof the duration during which the said rotary member effects a rotationthrough a certain angle and which is constituted by the said releasesignal and, on the other hand, by a second signal which represents themeasure of the degree of opening of the auxiliary throttling member.

In a preferred embodiment with the last-mentioned feature, the feeddevice'in which the said first signal is constituted, on each turn ofthe rotary member, by a release pulse whose beginning is concomitantwith the passage of the said rotary member through a fixed andpredetermined angular position and the said second signal is constitutedby a continuous voltage whose value depends on the degree of openin g ofthe auxiliary throttling member, is. characterized by the fact that thecomputing device includes a modulating member adapted to furnish, whenit is placed in action by the start of a release pulse,.an outputvoltage during a duration comprising a constant term and a termproportional to the value of input voltage furnished to the saidmodulating member, the output of the said modulating member beingconnected to its input through a loop in which are successivelyarranged, in series, an integrator adapted to integrate the outputvoltage during an interval of time comprised between the beginnings oftwo successive release pulses, a comparator adapted to effect thedifference between the output signal of the integrator and the saidsecond signal and a high gain amplifier adapted to transmit thisamplified difference to the input of the modulating member, theenergising signal being constituted by the output voltage of saidmodulating member.

According to another advantageous embodiment of the said improvement, afeed device in which the said first signal is constituted, on each turnof the rotary member, by a release pulse of which the duration isproportional to the duration during which the said rotary member effectsa rotation of a predetermined and constant angle and the said secondsignal is constituted by a continuous voltage whose value depends on thedegree of opening of the auxiliary throttle member, is characterized bythe fact that the computing device comprises an oscillator adapted todeliver pulses with a frequency depending on the value of the saidsecond signal and read-in and read-out means adapted, on each releasepulse, on one hand to read-in the number of pulses delivered by the saidoscillator during the duration of the release pulse and, on the otherhand, the read-out with a given and constant rythm the number of pulsesdelivered by the said oscillator during the duration of the precedingrelease pulse, these read-in and read-out means furnishing, on eachreading-out, a signal whose duration is proportional to the magnitude ofthe number of pulses read-out and which constitute the energisingsignal.

In order that the invention may be more fully understood, threeembodiments of the fuel feed device according to the invention aredescribed below, purely by way of illustrative but non-limitingexamples, with reference to the accompanying drawings, in which:

FIG. 1 shows diagrammatically portions in elevation and portionsremoved, of a first embodiment of a fuel feed device according to theinvention;

FIG. 2 shows, as a function of time, the charging and discharging curvesof the condenser forming a part of the embodiment of FIG. 1.

FIG. 3 shows diagrammatically, with portions in elevation and portionsremoved, a second embodiment of a fuel feed device according to theinvention;

FIG. 4 shows a table of curves illustrating the operation of thecomputing device of the embodiment shown in FIG. 3;

FIG. 5 shows in detailed manner a portion of the signal generator of theembodiment of FIG. 3;

FIG. 6 shows diagrammatically, with portions in elevation and portionsremoved, a third embodiment of the device according to the invention;and

FIG. 7, finally, shows a table of curves illustrating the operation ofthe computing device of the embodiment of FIG. 6.

According to the invention and more particularly according to that ofits methods of application, as well as those of its methods ofproduction of its various parts, to which it would appear thatpreference should be given and with a view to manufacturing a fuel feeddevice for a vehicle or a similar engine, the procedure is as follows orin analogous manner.

This device comprises, as shown in FIG. 1, 3 and 6: on one hand, in itsintake pipe 1, a main throttle member (or butterfly valve) 2 actuated bythe driver; on the other hand, a source S of fuel l under pressure whosedelivery cii'cuit, which opens into the portion of the intake pipe 1situated downstream of the main throttling member 2, is controlled by atleast one valve 3 actuated by an electromagnet 4;

on the other hand, finally, a metering system which, provided with arotary member 5 rotated continuously (in the direction of the arrowfofFIGS. 1, 3 and 6) is adapted to send into this electromagnet 4 anenergising signal during a fraction of each turn of said member 5 whichis regulated by this system.

This feed device comprises further, according to the invention, a signalgenerator 6 (FIG. 1), 6a (FIG. 3) or 6b (FIG. 6) adapted to apply, oneach turn of the said rotary member 5, a release signal which lastsduring a predetermined and constant fraction of a turn of the saidrotary member 5, to produce an energising signal whose duration variesin the same sense as that of the release signal and in the same sense asthe degree of opening of an auxiliary throttle member 8 which isarranged in the intake pipe I upstream of the main throttle member 2 andwhich is arranged to be opened automatically and progressively inproportion as the flow of air in said pipe 1 increases, the assemblybeing such that the fraction of each turn of said rotary member 5 duringwhich the energising signal is sent into the electromagnet 4 varies inthe same sense as the degree of opening of the auxiliary throttle member8.

In the embodiments of FIGS. 1, 3 and 6 (FIG. 6 being simplified withrespect to the others), the auxiliary throttle member 8 is constituted,for example, by a butterfly valve borne by an axle 9 on which is keyed alever 10 (situated outside the pipe 1) at the free end of which ishinged a tie-rod ll actuated by a pneumatic device. This pneumaticdevice comprises, for example, a diaphragm 12 which is connected to thetie-rod 11 and which separates two chambers 13 and 14 from one another.A pipe 15 places the chamber 13 in communication with the section of thepipe 1 which is included between the throttle members 2 and 8. A spring16 tends to push the diaphragm l2 and the tie-rod ll downward in FIGS.1, 3 and 6 hence to close the valve 8, against the action of thepressure transmitted through the pipe 15 and acting on said diaphragm12. The chamber 14 is placed at atmospheric pressure through a channel17 which opens preferably into the intake of the pipe 1, between an airfilter (not shown) and the valve 8. Finally, a cam 18 is keyed on theaxle 9, outside the pipe I.

It is seen that the angular position of the auxiliary throttle member 8or that of the axle 9 at any moment corresponds to the flow of air (flowof air by weight in unit time consumed by the engine) which flows inpipe 1 in the direction .of the arrow F.

The greater the flow of air, the greater the degree of opening of thevalve 8, a substantially constant suction (or varying according to thecharacteristics of the spring 16) is established between the twothrottle members 2 and 8.

The auxiliary throttle member 8 could be replaced by well-knownengineering equivalents, such as those described in British patentapplication No. 48,076/68 filed Oct. 10, 1968.

In the first embodiment shown in FIG. 1, the signal generator 6 may beconstituted by making it include an element 7, preferably a variableimpedance, sensitive to the position of the said auxiliary throttlemember 8 and having an influence on the duration of the energisingsignals furnished by the said generator.

In the embodiment of FIG. 1, the signal generator 6 is constituted bymaking it include a condenser 19, a variable resistance or rheostat 20and changeover switch means 21 adapted to actuate successively, on eachturn of the member 5, the charging of the condenser 19 during therotation of a predetermined and constant angle a of this member 5 andthe discharge of this condenser 19 into a circuit constituted by thevariable resistance 20 and a threshold device 46 connected in series,this threshold device 46 sending into the electromagnet 4 an energisingsignal as long as the discharge current is greater than a giventhreshold.

The said switch means 21 (which are shown in diagrammatic manner inFIG. 1) are advantageously with two stable states, a first state(effected through the connections in full lines) corresponding to thecharging of the condenser 19 through a battery 22 and a second state(effected through the connections in mixed lines) corresponding to thedischarge of the condenser 19, these means 21 being controlled by arelease signal furnished by a field sensor 23 in the vicinity of whichis rotated a magnetic mass 24 rigidly fixed to the rotary member 5.Rotation through a predetermined angle a of the magnetic mass 24generates, in the sensor 23, on each turn of the member 5, a releasesignal whose start actuates the placing in the first state of the saidswitch means 21 and of which the end actuates the placing in the secondstate of the said switch means 21. These switch means 21 as well as thethreshold device 46, known in themselves, may be formed by means ofrelays.

The variable resistance is advantageously constituted by a rheostatprovided with a movable slider 25 whose displacements are controlled bythe movements of the cam 18 which is rigidly fixed to the auxiliarythrottle member 8 and which comprises an active surface 26 bearing on amechanical connecting member 27 movable with the said slider 25.

The abovesaid mechanical connecting member 27 is constituted by a rod 28which can slide in a guide 29 and which is supported under the action ofa spring 30 against the active surface 26 of the cam 18, through aroller 31.

The speed of rotation of the rotary member 5 (constituted for exampleand as shown in FIG. 1 by an axle) not having influence on the overallduration of opening of the valve 3 since this duration only depends onthe fraction of each turn of the said member during which the said valveis open, the member 5 can be driven for example by a constant speedelectric motor.

However, if it is desired to cycle the injection of fuel, that is to sayto determine at which moment of each engine cycle the fuel injection ismade into the stream of air flowing in the pipe 1, it is preferable todrive the member 5 through the shaft of the internal combustion engine,by a transmission imposing on it a speed of rotation preferably amultiple of that of this shaft.

As regards the source of fuel S, it is preferably constituted, accordingto the three embodiments of FIGS. 1, 3 and 6, by the assembly of a pump32 (FIG. 1) which pumps the fuel into a reservoir (not shown) through asuction channel 33 and a pressure regulator 34 arranged on the supplychannel 35 ofthe pump. This regulator, known in itself, is adapted toplace into communication the channels 33 and 35 through an evacuationchannel 36 as soon as the pressure in the channel 35 exceeds apredetermined value.

As regards the delivery circuit, the electromagnet 4, whose supply isensured by conductors 37, 38 connected to the threshold device 46,actuates a rod 39 whose end, forming the valve 3, co-operates with aseat 40 connected to a delivery channel 35, the seat 40 end ing at acalibrated orifice 41 which opens into the pipe 1 (for reasons ofclarity, this arrangement of the calibrated orifice 41 with respect tothe pipe 1 is not shown in FIGS. 1, 3 and 6).

A spring 42 tends constantly to close the valve 3 whilst, when it isenergised, the electromagnet 4 opens this valve. It is advantageous toshield the injection orifice 41 from the influence of the suctionexisting in the pipe 1 downstream of the main throttle member 2. To thisend, the orifice 41 is made to open into a chamber 43 communicating withthe pipe 1 through an orifice 44 which is preferably aligned with theorifice 41 and whose section is preferably greater than that of thislatter orifice and the chamber 43 is connected to an aerating zone atsubstantially constant pressure through a channel 45 whose cross-sectionis distinctly greater than that of orifice 44.

The feed device shown in FIG. 1 operates as follows.

On each turn of the member 5, the magnetic mass 24 passing in front ofthe sensor 23 causes, during a certain angle of rotation (or fraction ofa turn) a, the emission by the sensor 23 of a release signal whosebeginning actuates the charging of the condenser 19 and whose endactuates the discharge of this condenser 19 into the variable resistance20 and into the threshold device 46, which actuates the opening of thevalve 3 and hence the injection of fuel as long as the discharge currentexceeds a determined threshold.

The operation of the signal generator is illustrated by FIG. 2 in whichare shown as abscissae the time t and as ordinate the voltage U at theterminals of the condenser 19.

Assuming that during the interval of time comprised between the momentst and t the magnetic mass 24 turns through an angle a in front of thesensor 23. The condenser 19 is then charged by the battery 22 and thevoltage U of this condenser increases along the curve 0C When the mass24 emerges from the limits of the angle a, at the moment t the condenser19 has acquired a charge U whose value is substantially proportional tothe interval of time A r z, t and consequently substantially inverselyproportional to the number of turns per second of the mass 24. 7

At the instant t the end of the release signal emerging from the sensor23 actuates the discharge of the condenser 19 whose voltage U decreasesalong the curve C C which reaches at the moment t the value for whichthe electromagnet 4 ceases to maintain the opening of the valve 3, thisvalve being then closed under the action of the spring 42..

The fraction of a turn G of the mass 24 during which the condenser 19 isdischarged and during which the valve 3 is open is expressed by theproduct:

G=(t t,) N-At'-N (I) N being the number of turns per second of the mass24 and A r the interval of time separating the moments t and If thecurves OC, and C C are compared with straight lines and if the anglebetween the curve C,C and the vertical passing through (C is called a,then:

At U tg a i (2 U being considered as the measure of the segment 0U, onthe axis 0U and At as the measure of the segment t t on Ot.

Moreover, U is substantially proportional to l/N, or:

U k/N (3) By combining (l), (2) and (3), there is obtained:

It is deduced therefrom that the fraction of a turn of the mass 24during which the valve 3 is open only depends on the value of the anglea.

The value of the angle a is determined, in the embodiment of FIG. 1, bythe value of the variable resistance 20, which is controlled by themovements of the cam 18 so that said fraction of a turn varies in thesame sense as the degree of opening of the auxiliary throttle member 8.

By successive experiments, the active surface 26 of the cam 18 can begiven a shape such that the said fraction of a turn is for exampleproportional to the flow of air in the pipe 1.

In FIG. 2, there is shown a discharge curve C,C correspnding to a flowof air less than in the case of the curve C,C the time of injection At"being also less than the time At.

It is self-evident that the embodiment of the fuel feed device which hasbeen described above is only one simple example and that he could alsoinclude a cold starting system such as described in US. Pat. No.3608533.

In addition, it may be advantageous to arrange the pressure regulator 34of the source S according to the arrangements in British patentapplication No. 48,076/68 of Oct. 10, 1968, so that this regulator fixesin the delivery channel 35 a pressure proportional to the air pressureexisting in the section of the pipe 1 situated between the throttlemembers 2 and 8 in order to adapt the fuel flow to the conditions ofacceleration.

Moreover, the rotary member may advantageously be a member existingalready in the engine, as for example the ignition distributor on whichit is easy to fix a rotary magnetic mass 24 turning in the vicinity of asensor 23.

It may also be noted that the rotary member does not necessarily have tobe driven by the internal combustion engine and that it can hence beseparated from the latter.

In the embodiments shown in FIGS. 3 to 6, the signal generator 6a (FIG.3) or 6b (FIG. 6) comprises a computing device 47a (FIG. 3) or 47b (FIG.6) adapted to furnish the above-defined energising signal starting, onone hand, from a first signal S, (FIG. 3) or S, (FIG. 6) whichrepresents the measurement of the duration during which the said turningmember 5 effects a rotation of a certain angle and which is constitutedby the abovesaid release signal and, on the other hand, by a secondsignal S (FIG. 3) or 8, (FIG. 6) which represents the measurement of thedegree of opening of the auxiliary throttle member 8.

In the case of the feed device of FIG. 3, the first signal S, (which isrepresented as a function of the time by a curve denoted by S, in thetable of FIG. 4) is constituted, on each turn of the rotary member 5, bya pulse which is emitted by the field sensor 23, the beginning of thepulse being concomitant with the passage of the magnetic mass 24 infront of the sensor 23 (position shown in FIG. 3). The interval of timeseparating the beginnings of two successive pulses of the signal S,represents the measurement of the duration during which the rotarymember 5 effects a rotation through an angle of 360.

The second signal S is obtained, like signal S of the device of FIG. 6,by a potentiometer 48 which is fed by the voltage source 22.

This potentiometer includes a movable slider 49 (on which is collectedthe signal S or S whose displacements are controlled like those of theslider 25 of the embodiment of FIG. 1.

The computing device 47a of the embodiment of FIG. 3 comprisesadvantageously a modulating member 50 adapted to supply, when it isplaced in action by the start of a pulse of the first signal 5,, anoutput voltage U, during a time T comprising a constant period To and aperiod k-u, proportional to the value of the input voltage u, furnishedto the said modulating member 50, the output 51 of the said modulatingmember 50 being connected to its input 52 through a loop 53 in which aresuccessively arranged, in series, an integrator 54 adapted to integratethe output voltage U, during an interval of time comprised between thecommencements of two successive pulses of the first signal S,, acomparator 55 adapted to effect the difference between the signalemerging from the integrator 54 and the second signal S, and a high gainamplifier 56 G adapted to transmit this amplified difference to theinput 52 of the modulating member 50, the energising signal beingconstituted by the output voltage U, ofthe modulating member 50.

In a preferred embodiment, the signal generator 6a comprises a flip flip57 with two control inputs 58 and 59 and two outputs 60 and 61.

The first input 58 is fed by the first signal S,, the second input 59 isfed by the output voltage U, of the modulating member 50, the firstoutput 60 being connected to an input 62 for placing in action themodulating member 50 and the second output 61 is adapted to furnish anenergising signal.

An energising signal is present at the second output 61 each time thatthe flip flip 57 is placed in a state whose beginning is controlled bythe beginning of a pulse of the signal S, (this state controllingthrough the output 60 and the input 62 the beginning of the outputvoltage U supplied by the modulating member 50) and whose end iscontrolled by the end of the output voltage U,.

In another advantageous arrangement, the energising signals aretransmitted to the electromagnet 4 through an electronic switch 63 whichis constituted by an AND gate of which one input 64 receives theenergising signals and of which the other input 65 is adapted to be fedby the comparison means 66.

These comparison means 66 are adapted to compare the period T of eachenergising signal with a corresponding fixed reference T preferably,with the period of the energising signal when the internal combustionengine of the vehicle is on idling and to control the opening or theclosing of an AND gate 63 so that the transmission of the energisingsignals to the electromagnet 4 is ensured when the duration of the saidenergising signal is greater than the period T and that the transmissionof the energising signals of the electromagnet 4 is interrupted when theperiod of the said energising signal is less than the period T Thesecomparison means 66 include advantageously a flip flop 67 of which afirst control input 68 is connected to the output 69 of an AND gate ofwhich one input 71 is fed, through an inverter 72, by energising signalsemerging from the output 61 of the flip flop 57. The other input 73 ofthe AND gate is connected to the output 74 of a monostable flip flop 75whose input 76 is supplied by the said energising signals. The secondcontrol input 77 of the flip flop 67 is connected to the output 78 of anAND gate 79 of which one input 80 is connected, through an inverter 81,to the output 74 of the flip flop 75 and whose other input 82 is fed bythe energising signals.

The monostable flip flop 75 delivers pulses of which the beginningcoincides with the beginning of the energising signals and of which theperiod is equal to T The bistable flip flop 67 feeds through its output83 andthe input 65 of the AND gate 63 so that, when the said flip flop67 occupies a first state which is controlled by one or more of thepulses sent into its input 68, the AND gate 63 interrupts thetransmission of the energising signals and that, when the said flip flop67 occupies a second state which is controlled by one or more of thepulses sent into its input 77, the AND gate 63 ensures the transmissionof the energising signals.

The energising signals present at the output 84 of the AND gate 63 areadvantageously applied to the electromagnet 4 by a power relay 85.

The operation of the embodiment of the feed device of FIG. 3 will now bedescribed with the aid of the table of FIG. 4.

In this table, there is shown as a function of time the first signal 8,,the signal a present at the output 61 of the flip flop 57, the signal bpresent at the output 60 of the flip flop 57, the output voltage U, ofthe modulating member 50, the signal present at the output 84 of the ANDgate 63, the signal d supplied by the relay 85 to the electromagnet 4,the signal e present at the output 74 of the monostable flip flop 75,the signal f present at the output 69 of the AND gate 70, the signal gpresent at the output 78 of the AND gate 79 and the signal it present atthe input 65 of the AND gate 63.

It is assumed that at the moment t a pulse of the first signal S arrivesat the input 58 of the flip flop 57. This pulse controls a change ofstate of the flip flop 57 on the output 61 of which appears a signal aof value 1" as shown by the table of FIG. 4. At the same time, thereappears on the output 60 a signal b of value 0 and the descending fromof this signal b actuates the placing in operation of the modulatingmember 50 which supplies on its outputSl an output voltage U, of whichit is assumed that it has a constant amplitude and equal to U Thisvoltage U has, thus as has already been explained, a duration T whichmay be expressed by:

T: T [CH and of which it will be seen below that it corresponds well tothe conditions of duration of the energising signal.

Atthe moment t, which marks the end of the output voltage U,, thedescending front of the said output voltage U, actuates the change ofstate of the flip flop 57, the signal a taking the value 0" and thesignal b taking the value l The signal a,, of which the durection in thestate 1", is equal to the duration of the output voltage U,, is sentonto the input 64 of the ANd gate 63 and, if the input 65 of the saidANd gate 63 is fed by a signal h of valve l the ANd gate 63 transmitsonto its output 84 a signal c analogous to the signal a,.

The cycle described above is reproduced on each release pulse of thesignal S, and the relay 85 thus supplies, on each pulse of the signal Sand hence on each turn of the rotary member 5, an energising signal ofwhich the amplitude is for example equal to Ue and of which the durationis equal to T (signal d).

The signal e shows the pulses of duration T which are present at theoutput 74 of the monostable flip flop and of which the beginnings areconcomitant with the beginnings of the output voltages U In the casewhere T is greater than T to each output voltage U, there corresponds apulse (signal g) which is applied on the input 77 of the bistable flipflop 67 and which places or holds this flip flop 67 in a state for whicha signal h of value l is present on its output 83. The ANd gate 63therefore transmits the energising signals.

In the case where T is less than T to each output voltage U, correspondsa pulse (signal f1) which is applied on the input 68 of the bistableflip flop 67 and which places or holds this flip flop 67 in a state forwhich a signal h of value 0 is present on its output 83. The AND gate 63then interrupts the transmission of energising signals.

Thus, in the table of FIG. 4, the three first energising signals haveaduration T greater than T and the AND gate 63 transmits them to therelay which supplies a signal d.

The fifth energising signal, of which the beginning intervenes at themoment has a duration T less than the duration T (as a result ofmodification of the degree of opening of the auxiliary throttle member8) and the pulse (signal f1) which results therefrom, causes the signalh to pass from the value 1 to the value 0, which interrupts thetransmission of the sixth energising signal, interventing at the momentt through the AND gate 63.

As regards the computing device 47a, the signal S has a value:

2 U0 fl (4) U0 (chosen as equal, for reasons of simplification, as theamplitude U0 of the output voltage U being the voltage of the source 22and f (a) a function of which the value varies in the earns sense as theair flow a.

The comparator 55 delivers a voltage:

2 y y being the output voltage of the integrator 54.

The amplifier S6 of high gain G delivers a voltage:

u, G e (6) The modulating member 50 produces, on each pulse of thesignal 8,, a voltage U of which the amplitude is U0 and of which theduration is:

The period 1- 'of the pulses of the first signal S, is:

7 l/ N (8) N being the number of turns per second of the rotary member5.

The integrator 54 supplies a voltage y-which represents the averagevalue of the actuating voltage U, between two pulses of the signal 8,;thus:

By combining the equations (1) to (6), one obtains:

To/[l kGU0(N/k1l)] /k1)l it/ (H) G being very large, one obtains: T=(k/N) '(S /U0) namely: (12") l 'f( (is) As a result the fraction T'N ofeach turn of the rotary member 5 during which the energising signal issent to the electromagnet 4 and during which the valve 3 permits theinjection of fuel into pipe 1 depends only on the degree of opening ofthe auxiliary throttle member 8.

The functionf(a) depends on the shape of the active surface 26 of thecam 18 and, by successive experiments, there can be. given to thisactive surface 26 a shape such that the function f (a) and the fractionof a turn concerned have values for example proportional to the flow ofair in pipe 1.

FIG. shows in detail an embodiment of the computing device 47a formingpart of the signal generator 6a already described.

This computing device 47a, which is supplied by a battery 110 andthrough a static converter 111, comprises the same elements as thecomputing device 47a of FIG. 3, namely a modulating member 50, anintegrator 54, a comparator 55 and an amplifier 56, constituted by adifferential amplifier A producing both the comparison between thesecond signal S emerging from the potentiometer 48 and the signal yemerging from the integrator 54 and the amplification of the difference6 between S and y.

The modulating member 50 comprises p-n-p transistors T and T which areconnected through their bases 112 and 113 to the output 60 of the flipflop 57 and which control respectively n-p-n transistors T and T Acondenser 114 is connected with the emitter 115 and the collector 116 ofthe transistor T and a p-n-p transistor T which is mounted in thecurrent source, supplies the junction 117 between the collector 116 ofthe transistors T and the condenser 114, with current.

The modulating member 50 comprises also a differential amplifier Aformed by n-p-n transistors T and T of which the emitters 118 and 119are connected in parallel to the collector circuit 120 of an n-p-ntransistor T mounted in the current source. This differential amplifierA is adapted to compare the voltage existing at the junction 117 withthe voltage occurring at the output 121 of the differential amplifier AIn the collector circuit 122 of the transistor T is arranged aresistance R of which one terminal 123 is connected to the base 124 ofap-n-p transistor T This transistor T controls an n-p-n transistor T inthe collector circuit 125 of which is arranged a resistance R of whichone terminal 126 is connected to the input 59 of the flip flop 57.

The integrator 54 comprises two p.n.p. transistors T and T which arerespectively controlled by the transistors T and T and of which theemitters 127 and 128 are connected to a junction 129. The integrator 54comprises again a low-pass filter 130 which is formed by resistances Rand R and a condenser 131. The input 132 of this filter is connected tothe junction 129 and the output 133 of the said filter is connected tothe negative input 134 of the differential amplifier A The positiveinput 135 of this amplifier A is connected to the slider 49 of thepotentiometer 48.

Between the inputs 134 and 135 of the amplifier A are arranged diodes136 and 137 mounted head-to-tail.

1n the base circuit 138 of the transistor T are mounted in parallelresistances R and R of which one (the resistance R may be placed in orout of the circuit according to the position of change-over switch 139.

A second change-over switch 140, of which the position is controlled atthe same time as that of the change-over switch 139, can, according toits position, place resistances R and R in parallel or not with theresistances R and R There will now be described the operation of thiscomputing device 47a. Assuming that the input voltage 11 is supplied tothe modulating member 50 and that the transistors T T T T T T are in aconductive state whilst the transistors T T T and T are in a blockedstate.

At the moment to, a pulse of the first signal S, appears at the input 58of the flip flop 57. This pulse actuates a change of state of the flipflop 57 on the output 61 of which appears the signal a of value l asshown in the table of FIG. 4. At the same time there appears on theoutput 60 a signal b of value 0" which blocks the transistors T and TThe transistor T puts into a conductive state the transistor T and thetransistor T places in a blocked state the transistor T The constantcurrent, which is provided by the transistor T and which, before themoment to, passes through the transistor T then charges the condenser114. When the voltage at the junction 117 becomes equal to the voltage aat the output of the differential amplifier A the transistor T of thedifferential amplifier A becomes conductive and conducts a portion ofthe constant current supplied through the transistor T which places in aconductive state transistors T and T The drop in voltage caused at theterminal 126 of the resistance R; by the placing of the transistor T ina conductive state restores the flip flop 57 into the state that it hadbefore the arrival at the moment to of a pulse of the first signal S thesignal a taking the value 0 and the signal b taking the value 1". Thesignal b of value 1 places the transistors T and T in a conductivestate. The transistor T places the transistor T in a conductive statewhich enables a rapid discharge of the condenser 114 and the transistorT places the transistor T in a blocked state. The discharge of thecondenser 114 brings about the placing in a blocked state of thetransistor T which controls the placing in a blocked state oftransistors 1 and T It is seen that it is thus reobtained the conditionsfixed at the start and that the modulating member 50 is ready to effectthe above-described operations on the arrival of a new pulse of thefirst signal 8,.

As regards the duration T during which the flip flop 57 occupies a statefor which the signal b has a value l which duration corresponds to thatof the energising signal of the electromagnet 4 and which must be equalto T To ku it wll now be verified that it corresponds well to theoperation of the modulating member 50.

It will be assumed that the line 141 is at a supply voltage +V, that theline 142 is at a supply voltage OV. that the line 143 is at a supplyvoltage V and there will be taken into account the existence of aresistance R con necting the base 138 of the transistor T to the line142 and of a resistance R connecting the emitter 144 of the transistor Tto the line 141.

The voltage V at the junction 117 depends on the charge of the condenser114 and is expressed by V io/C t if [0 is the charging current suppliedthrough the transistor T Designating R as the equivalent resistance toresistances R and R one has By putting R R [(R R )/R,]. one has Theduration T that the condenser 114 is charged so that the voltage Vbecomes equal to the voltage V has:

at the output 121 of the differential amplifier A, is given by:

121 uCm Now, by taking V from the zero volt level, one

There is thus obtained:

T: y'Cmf 191C115 t/XL... t

By comparison with the equation T= T ku given above, there is obtained:

T0 RUICIH and k R 'C /V The modulating member 50 hence controls thechange of state of the flip flop 57 after a duration comprising aconstant period To and a period ku proportional to the value of thevoltage u Now as regards the integrator 54 which produces the voltageu,, it has been seen that the transistor T was placed in a conductivestate during the period T of each pulse of the energising signal. Whenit is in this conductive state, the transistor T puts the transistor Tin a conductive state and puts in its blocked state the transistor Tand, when this transistor T is in its blocked state, it puts thetransistor T in its blocked state and the transistor T in its conductivestate. Consequently, the junction 129 is placed at a potential in theneighbourhood of the supply voltage +V for periods T and it is placed ata potential in the neighbourhood of the voltage 0V during the intervalsof time separating the periods T. The low-pass filter 130 supplies toits output 133 an average value of the voltage existing at the junction129, which average value varies in the same sense as the periods T andin a sense contrary to the intervals of time separating the two pulsesof the first signal S\.'

On starting the engine, it is convenient, on one hand, to increase theperiods T of the energising' signals, and on the other hand, to increaseintegration time constant of the low pass filter 130.

To do this, resistances R R and R are placed out of circuit, onstarting, by change-over switches 139 and.

140 and are later placed in circuit.

The diodes 136 and 137 have the role oflimiting the difference betweenthe voltages u, and S in order not to overload the amplifier A,.

Now as regards the feed device of FIG. 6, the first signal S, (which isshown as a function of time by a curve denoted by S, in the table ofFIG. 7) is constituted, on each turn of the rotary member 5, by arelease pulse which is emitted by the field sensor 23, the duration ofeach release pulse being proportional to the duration during which thesaid rotary member effects a rotation of a predetermined and constantangle r.

The second signal S is similar to signal S and is obtained by meansanalogous to those which have already been described with relation tothe device of FIG. 3.

The computing device 47b of the device of FIG. 6 comprisesadvantageously an oscillator 88 (such as an overcoupled oscillator)adapted to deliver pulses with a frequency F dependent on the value ofthe second signal 8 and of reading in and reading out means adapted, oneach release pulse of the first signal 8,, on one hand, to read in thenumber of pulses delivered by the said oscillator 88 during the periodof the release pulse and. on the other hand, to read out with a givenand constant rythm the number of pulses delivered by the said oscillator88 during the period of the preceding release pulse, these reading inand reading out means providing, on each reading out, a signal of whichthe duration is proportional to the magnitude of the number of pulsesread out and which constitutes the energising signal.

According to a preferred embodiment, the reading in and reading outmeans comprise a totalisator 89 provided with a first memory 90 adaptedto read in the number of pulses delivered by the oscillator 88 duringthe period of a release pulse and a second memory 91 adapted to recordthis number and to provide, under the action of a generation 92 ofpulses read out at a fixed frequency F a signal constituted by asuccession of this same number of read out pulses, the said successionof read out pulses being applied to a decoding member 93 adapted tofurnish an output voltage constituting the energisingsignal during aperiod equal to that of the said succession of read out pulses.

These read in and read out means include again a first electronic switch94 (constituted by an AND gate) of which one input 95 is supplied by thefirst signal 5,, of which another input 96 is supplied by pulsesfurnished by the oscillator 88 and of which the output 97 is connectedto the input 98 of the memory 90. The AND gate 94 transmits to thememory 90 pulses supplied by the oscillator 8 when a release pulse ispresent on its input 95 and interrupts this transmission when no releasepulse is presente on its input 95.

Read in and read out means comprising also a second electronic switch 99(constituted by an AND gate) of which one input 100 is fed by read outpulses furnished by the generator 92 and of which the output 101 isconnectedto the read out input 102 of the memory 91.

These read in and read out means comprise also a flip flop 103 with twocontrol inputs 104 and 105 and two outputs 106 and 107.

The first input 104 is supplied by the first signal S,, the second input105 is fed by the output voltage of the decoding member 93, the firstoutput 106 is connected to a negative input 108 of the AND gate 99 andthe second output 107 is adapted to furnish energising signals.

An energising signal is present on the second output 107 each time thatthe flip flop 103 is placed in a condition of which the beginning iscontrolled by the commencement of a release pulse of signal S, (thebeginning of this release pulse controlling the beginning of reading inby the memory 90 of pulses furnished by the oscillaton 88 and theplacing in the above-mentioned state of the flip flop 103 controlling,by the output 106 and the input 108, the beginning of reading out of thenumber contained in the memory 91) and of which the end is controlled bythe end of the output voltage of the decoding member 93..

The end of the output voltage of the decoding member 93 is also applied,by means not shown which are known in themselves, to transfer into thememory 91 the number which is contained in the memory 90, this lattermemory being thus emptied and ready to effect a new reading in.

According to an arrangement analogous to that of the feed device of FIG.3, the energising signals present on the output 107 of the flip flop 103are transmitted to the electromagnet 4 by means of an electronic switch109 which is constituted by an AND gate of which one input 86 receivesthe energising signals and of which the other input 87 is supplied bythe comparison means 66.

These comparison means 66 are identical to those which have already beendescribed with relation to FIG. 3 and compare the duration T of eachenergising magnet 4 by a relay 85 and the injection means for fuel intothe pipe 1 are similar to those of FIGS. 1 and 3, an

energising signal for the opening of the valve 3 and the injection offuel.

The operation of the feed device of FIG. 6 will now be described bymeans of the table of FIG. 7.

In this table, there is shown, as a function of time, the first signal8,, the content C, of the first memory 90, the content C of the secondmemory 91, the signal i present at the output 107 of the flip flop 103,the signal j present at the output 106 of the flip flop 103, the signalI present at the input 105 of the flip flop 103, the signal m suppliedby comparison means 66 at the input 87 of the AND gate 109 and thesignal n supplied by the relay 85 to the electromagnet 4.

It will be assumed that at the moment to, a release pulse of the firstsignal S, is applied on the input 95 of the AND gate 94 and on the input104 of the flip flop 103. It will be assumed also that the memory 91contains a number p.

The beginning of this release pulse enables the transmission, throughthe AND gate 94 of pulses emerging from the oscillator 88 to the memory90 which reads in these pulses as long as the release pulse lasts, thecontents of the memory 90 passing from to the number p (curve C,).

The beginning of this release pulse places the flip flop 103 in a statefor which the signal 1' takes a value l and the signal j a value 0. Thissignal j of value 0 permits the transmission through the AND gate 99 ofread out pulses of constant frequency F emerging from the generator 92to the memore 91 of which the contents C decreases regularly and passesfrom the number 2 to the number 0 which is obtained at a moment 1,.

Between the moments to and 1,. the decoding member 93 supplies thereforeto the input 105 of the flip flop 103 a voltage (signal I) of which theend controls the changing of state of the flip flop 103, the signal 1'taking the value 0 and the signalj the value 1.

This change of state is applied to transfer into the memory 91 thenumber p contained in the memory 90, this latter memory being restoredto zero.

This cycle is renewed on the arrival, at the moment ofa new releasepulse and it goes on in the same way for each new release pulse.

If the AND gate 109 allows the transmission of signals, the energizingsignals formed by each of the pulses of the signal 1' are transmitted tothe electromagnet 4 through a relay 85 of which the actuating signal nis formed by a succession of pulses each having a duration equal to thatof the corresponding energising signal. This is the case with energisingsignals corresponding to the release pulses supervening at moments toand ln the case of the energising signal corresponding to the releasepulse supervening at the moment t it has been assumed that, as a resultof modification of the degree of opening of the auxiliary throttlemember 8, the number p read in at each turn of the rotary member 5 bythe memory 90 was less than the preceding number p and that therethereby resulted an energising signal having a duration T less than thereference duration T The comparison means 66 then actuate theinterruption of the transmission of signals through the AND gate 109 andthe electromagnet 4 is not energised. 5 As regards the read in and readout means it has been seen that they provide, on each turn of the rotarymember 5, an energising signal on the output 107 of the flip flop 103,the duration T of this energising signal will not be calculated.

It will be assumed that the rotary member 5 rotates at the speed of Nturns per second. The duration of each release pulse of the signal S, ishence equal to (r/360) (l/N) and the number p which is read in by thememory 90 on each release pulse is hence equal to (r/360) (l/N) F if F,is the frequency of the oscillator 88.

It will be assumed that:

F,=Fo-f(a) (11 f(a) being a function of which the value varies in thesame sense as the degree of opening a of the auxiliary throttle member 8and F0 being a fixed frequency.

The time T applied by the generator 92 to effect the reading out of thisnumber pin the memory 91 is equal to:

F being the fixed frequency of the generator 92.

By combining the equations (11) and (12) and by taking into account theconstant terms, there is obtained:

As a result the fraction T'N of each turn of the rotary member 5, duringwhich the energising signal is sent to the electromagnet 4 and duringwhich the valve 3 allows the injection of fuel into the pipe 1, dependsonly on the degree of opening of the auxiliary throttle member 8.

Just as in the feed device of FIG. 3, the speed of rota tion of therotary member 5 has no influence on the value of this fraction of aturn.

The function flu) depends against on the shape of the active surface 26of the cam 18 and may be determined experimentally.

As regards the comparison means 66, they suppress the injection of fuelinto the pipe 1 of the internal combustion engine when this engineoperates under conditions which enable the supply of fuel to be cut off,especially when the engine is driven by the vehicle (deceleration).

Finally, whatever the embodiment adopted, in the case where it isnecessary to control a plurality of valves 3, there may be envisagedhaving as many signal generators and sensors 23 as electromagnets 4 tobe controlled or there may be provided a rotary member 5 on which arekeyed a corresponding number of magnetic masses 24 rotating in thevicinity of a single sensor 23 releasing a single signal generator, adistributor enabling the energising signals supplied by the generator tobe directed to the corresponding electromagnets.

Finally, whatever the embodiment adopted, there is obtained a compact,simple and economic device.

In particular, the adjustment of the fraction of a turn is effected byan electronic method and no longer by a mechanical method. Theconnection between the rotary member 5 and the signal generator 6, 6a or611, controlling the opening of the valves 3 in the delivery circuit, isdone by electrical conductors, which simplifies distinctly thepositioning of the feed device.

ln addition, the durations of the energising signals controlling theinjection are calculated with a great precision by the computingdevices.

As is self-evident, and as results also already from the precedingdescription, the invention is in no way limited to those of itsembodiments, nor to those of its methods of production of its variousparts, which have been more particularly indicated; it embraces, on thecontrary, all variations.

1 claim:

1. A fuel feed device for internal combustion engines comprising, in anintake pipe of the engine, a main throttle member actuated by thedriver, a source of fuel under pressure, a delivery circuit in fluidcommunication with said fuel source and which opens into the portion ofthe intake pipe situated downstream of the main throttle member, atleast one valve'positioned to control said delivery circuit, anelectromagnet in operative relationship for actuating said valve, and ametering system which comprises a rotary member rotated continuously andindependently from any necessary synchronization with said engine and anauxiliary throttle member and arranged to be opened or closedautomatically and progressively to a degree which is a function of theflow rate of air in said pipe as it increases or decreases respectively,said metering system being adapted to send into the electromagnet atleast one energizing signal during a fraction of each turn of the rotarymember, said fraction varying in proportion only as the degree ofopening of auxiliary throttle member, which is governed by said flowrate of air, the metering system comprising means operatively associatedwith said rotary member for generating a first electrical signal on eachturn of the rotary member, means sensitive to the degree of opening ofthe auxiliary throttle member for generating a second electrical signalrepresentative of the degree of opening of said auxiliary throttlemember, and signal forming means receiving said second signal andresponsive to each said first signal for generating one of saidenergizing signals during a fraction of the corresponding turn of therotary member which is a function of said second signal only.

2. Device according to claim 1, wherein the generator of electricalsignals comprises a'capacitor, a variable resistance sensitive to theposition of the said auxiliary throttle member and switch means adaptedto control successively, and at each turn of the rotary member, thecharge of said capacitor during rotation of a predetermined angle (a) ofthis rotary member and the discharge of said capacitor into the circuitconstituted by the variable resistance and by a threshold deviceconnected in series, the threshold device sending into the electromagnetan energising signal as long as the discharge current is higher than agiven threshold.

3. Device according to claim 2, wherein the switch means have two stablestates, a first state corresponding to the charging of the capacitor anda second state corresponding to the discharging of the capacitor, saidmeans being controlled by a signal furnished by a field sensor in theneighbourhood of which is rotated a magnetic mass rigidly fixed to saidrotary member, a rotation of a predetermined angle (a) of the magneticmass generating in the sensor, on each turn of said rotary member, arelease signal of which the start actuates the placing in the firststate of said switch means and of which the end actuates the placing inthe second state of said switch means.

4. Device according to claim 2, wherein the variable resistance isconstituted by a rheostat provided with a movable slider whosedisplacements are actuated by the movements of a cam which is rigidlyfixed to the auxiliary throttle member and which comprises an activesurface bearing on a mechanical connecting member movable with saidslider.

5. A fuel feed device for an internal combustion engine having an intakepipe and a driver actuated main throttle member in said pipe, saiddevice including:

at least one valve for delivering fuel under pressure to a portion ofthe intake pipe of the engine downstream of said main throttle member,said valve being ofa type substantially insentitive to the pressureprevailing in said intake pipe,

electro-magnetic means for opening said valve upon energization thereof,

an auxiliary throttle member located in said intake pipe upstream of themain throttle member and arranged to be opened automatically andprogressively in proportion with increase of the flow rate of air insaid intake pipe,

fuel pressure regulator means responsive to the pressure in said intakepipe for delivering fuel to said valve under a pressure which issubstantially proportional to the air pressure in said intake pipebetween said auxiliary throttle member and main throttle member,

and a fuel metering system for delivering to said electromagnetic meanselectrical actuating pulses for opening said valve, said metering systemcomprising means for generating a sequence of first electrical signalsindependently from any necessary synchronization with said engine andelectrical circuit means controlled by said auxiliary throttle memberfor generating, responsive to each said first electrical signal, anenergizing signal during a time which is a fraction of the time periodbetween two successive said first signals which depends on the positionof said auxiliary throttle member only.

6. A fuel feed device according to claim 5, wherein said means forgenerating a first electrical signal comprises a rotary member rotatedcontinuously and independently from any necessary synchronization withsaid engine, and means for generating one of said first electricalsignals on each turn of the rotary member.

7. A fuel feed device according to claim 6, wherein said electricalcircuit means comprises signal forming means connected to receive saidfirst signal and including an electrical component whose value iscontrolled by said auxiliary throttle member, whereby an energizingsignal is delivered responsive to each said first electrical signal andduring a time which is a fraction of the duration of the correspondingturn of the rotary member which is a function of said degree of openingonly, and said fraction remains constant so long as the flow rate of airin the intake pipe remains constant.

8. Device according to claim 5, wherein said signal forming meanscomprises a computing device adapted to provide said energizing signalfrom said first signal which begins when said member is in apredetermined angular position and ends when said rotary member haseffected a rotation of a predetermined angle and a sec ond signal whichrepresents the measurement of the degree of opening of the auxiliarythrottle member.

9. Feed device according to claim 8, wherein said first signal isconstituted, on each turn of the rotary member, by a release pulse ofwhich the beginning is concomitant with the passage of said rotarymember through a fixed and predetermined angular position and saidsecond signal is constituted by a continuous voltage whose value dependson the degree of opening of the auxiliary throttle member, and whereinsaid computing device comprises a modulation member adapted to furnish,when it is placed in action by the beginning of a release pulse, anoutput voltage for a time comprising a constant period and a periodproportional to the value of an input voltage furnished to saidmodulation member, the output of said modulation member being connectedto its input through a loop in which are arranged successively, inseries, an integrator adapted to integrate the output voltage during aninterval of time comprised between the commencements of two successiverelease pulses, a comparator adapted to effect the difference betweenthe output signal of the integrator and said second signal and a highgain amplifier adapted to transmit said difference amplified to theinput of the modulating member, the energising signal being constitutedby the output voltage of said modulating member.

10. Feed device according to claim 8, in which said first signal isconstituted, on each turn of said rotary member, by a release pulsewhose duration is proportional to the duration during which said rotarymember effects a rotation of a predetermined and constant angle and saidsecond signal is constituted by a continuous voltage whose value dependson the degree of opening of the auxiliary throttling member, wherein thecomputing device comprises an oscillator adapted to deliver pulses witha frequency dependent on the value of said second signal and reading inand reading out means adapted, on each release pulse, on one hand, tocount the number of pulses delivered by said oscillator during theduration of the release pulse and, on the other hand, to read out with agiven and constant rythm the number of pulses delivered by saidoscillator during the duration of the preceding release pulse, saidreading in and reading out means providing, on each reading out a signalwhose duration is proportional to the magnitude of the number of pulsesread out and which constitutes the energising signal.

11. Feed device according to claim 9, wherein the signal forming meanscomprises a flip flop with two actuating inputs and two outputs, thefirst actuating input being fed by the first signal, the secondactuating input being fed by the output voltage of the modulatingmember, the first output being connected to an input for bringing intoaction the modulating member and the second output being adapted tofurnish the energising signal, said energising signal being present onthe second output when the flip flop is placed in a state whose start isactuated by the beginning of the rlease pulse and whose end is actuatedby the end of the output voltage furnished by the modulating member.

12. Feed device according to claim 10, wherein the reading in andreading out means comprise a summation means provided with a firstmemory adapted to 5 read in the number of pulses delivered by theoscillator during the duration of a release pulse and a second memoryadapted to record said number and to provide, under the action ofagenerator of fixed frequency readout pulses, a signal constituted by asuccession of said same number of read-out pulses, the succession ofread-out pulses being applied to a decoding member adapted to supply anoutput voltage constituting the energising signal for a duration equalto that of said succession of read-out pulses.

13. Feed device according to claim 12, wherein the readin and read-outmeans comprise a first electronic switch which is interposed between thefirst memory and the oscillator and which is actuated by the firstsignal so that the pulses delivered by the oscillator are onlytransmitted to the first memory during the dura tion of the releasepulse, a second electronic switch which is interposed between theread-out pulse generator and the second memory and which is actuated bythe first signal so that the pulses delivered by the readout pulsegenerator are transmitted to the second memory from the beginning of therelease pulse of the first signal and a flip flop with two actuatinginputs and two outputs, the first actuating input being supplied by thefirst signal, the second actuating input being fed by the output voltageof the decoding member, the first output being connected to theactuating input of the second electronic switch and a second outputbeing adapted to supply the energising signal, said energising signalbeing present on the second output when the flip flop is placed in astate whose beginning is actuated by the beginning of the release pulseand whose end is actuated by the end of the output voltage of thedecoding member.

14. Feed device according to claim 8, wherein the energising signal istransmitted to the electromagnet through an electronic switch which isactuated by comparison means adapted to compare the duration of eachenergising signal to a corresponding flxed reference duration, so thatsaid switch is closed and ensures the transmission of energising signalsto the electromagnet when the duration of said energising signals isgreater than said reference duration and said switch is open and doesnot transmit energising signals to the electromagnet when the durationof said signals is less than the reference duration.

15. Fuel feed device according to claim 14, wherein said fixed referenceduration is the duration of the energising signal when the internalcombustion engine operates at slow speed.

1. A fuel feed device for internal combustion engines comprising, in anintake pipe of the engine, a main throttle member actuated by thedriver, a source of fuel under pressure, a delivery circuit in fluidcommunication with said fuel source and which opens into the portion ofthe intake pipe situated downstream of the main throttle member, atleast one valve positioned to control said delivery circuit, anelectromagnet in operative relationship for actuating said valve, and ametering system which comprises a rotary member rotated continuously andindependently from any necessary synchronization with said engine and anauxiliary throttle member and arranged to be opened or closedautomatically and progressively to a degree which is a function of theflow rate of air in said pipe as it increases or decreases respectively,said metering system being adapted to send into the electromagnet atleast one energizing signal during a fraction of each turn of the rotarymember, said fraction varying in proportion only as the degree ofopening of auxiliary throttle member, which is governed by said flowrate of air, the metering system comprising means operatively associatedwith said rotary member for generating a first electrical signal on eachturn of the rotary member, means sensitive to the degree of opening ofthe auxiliary throttle member for generating a second electrical signalrepresentative of the degree of opening of said auxiliary throttlemember, and signal forming means receiving said second signal andresponsive to each said first signal for generating one of saidenergizing signals during a fraction of the corresponding turn of therotary member which is a function of said second signal only.
 2. Deviceaccording to claim 1, wherein the generator of electrical signalscomprises a capacitor, a variable resistance sensitive to the positionof the said auxiliary throttle member and switch means adapted tocontrol successively, and at each turn of the rotary member, the chargeof said capacitor during rotation of a predetermined angle (a) of thisrotary member and the discharge of said capacitor into the circuitconstituted by the variable resistance and by a threshold deviceconnected in series, the threshold device sending into the electromagnetan energising signal as long as the discharge current is higher than agiven threshold.
 3. Device according to claim 2, wherein the switchmeans have two stable states, a first state corresponding to thecharging of the capacitor and a second state corresponding to thedischarging of the capacitor, said means being controlled by a signalfurnished by a field sensor in the neighbourhood of which is rotated amagnetic mass rigidly fixed to said rotary member, a rotation of apredetermined angle (a) of the magnetic mass generating in the sensor,on each turn of said rotary member, a release signal of which the startactuates the placing in the first state of said switch means and ofwhich the end actuates the placing in the second state of said switchmeans.
 4. Device according to claim 2, wherein the variable resistanceis constituted by a rheostat provided with a movable slider whosedisplacements are actuated by the movements of a cam which is rigidlyfixed to the auxiliary throttle member and which comprises an activesurface bearing on a mechanical connecting member movable with saidslider.
 5. A fuel feed device for an internal combustion engine havingan intake pipe and a driver actuated main throttle member in said pipe,said device including: at least one valve for delivering fuel underpressure to a portion of the intake pipe of the engine downstream ofsaid main throttle member, said valve being of a type substantiallyinsentitive to the pressure prevailing in said intake pipe,electro-magnetic means for opening said valve upon energization thereof,an auxiliary throttle member located in said intake pipe upstream of themain throttle member and arranged to be opened automatically andprogressively in proportion with increase of the flow rate of air insaid intake pipe, fuel pressure regulator means responsive to thepressure in said intake pipe for delivering fuel to said valve under apressure which is substantially proportional to the air pressure in saidintake pipe between said auxiliary throttle member and main throttlemember, and a fuel metering system for delivering to saidelectromagnetic means electrical actuating pulses for opening saidvalve, said metering system comprising means for generating a sequenceof first electrical signals independently from any necessarysynchronization with said engine and electrical circuit means controlledby said auxiliary throttle member for generating, responsive to eachsaid first electrical signal, an energizing signal during a time whichis a fraction of the time period between two successive said firstsignals which depends on the position of said auxiliary throttle memberonly.
 6. A fuel feed device according to claim 5, wherein said means forgenerating a first electrical signal comprises a rotary member rotatedcontinuously and independently from any necessary synchronization withsaid engine, and means for generating one of said first electricalsignals on each turn of the rotary member.
 7. A fuel feed deviceaccording to claim 6, wherein said electrical circuit means comprisessignal forming means connected to receive said first signal andincluding an electrical component whose value is controlled by saidauxiliary throttle member, whereby an energizing signal is deliveredresponsive to each said first electrical signal and during a time whichis a fraction of the duration of the corresponding turn of the rotarymember which is a function of said degree of opening only, and saidfraction remains constant so long as the flow rate of air in the intakepipe remains constant.
 8. Device according to claim 5, wherein saidsignal forming means comprises a computing device adapted to providesaid energizing signal from said first signal which begins when saidmember is in a predetermined angular position and ends when said rotarymember has effected a rotation of a predetermined angle and a secondsignal which represents the measurement of the degree of opening of theauxiliary throttle member.
 9. Feed device according to claim 8, whereinsaid first signal is constituted, on each turn of the rotary member, bya release pulse of which the beginning is concomitant with the passageof said rotary member through a fixed and predetermined angular positionand said second signal is constituted by a continuous voltage whosevalue depends on the degree of opening of the auxiliary throttle member,and wherein said computing device comprises a modulation member adaptedto furnish, when it is placed in action by the beginning of a releasepulse, an output voltage for a time comprising a constant period and aperiod proportional to the value of an input voltage furnished to saidmodulation member, the output of said modulation member being connectedto its input through a loop in which are arranged successively, inseries, an integrator adapted to integrate the output voltage during aninterval of time comprised between the commencements of two successiverelease pulses, a comparator adapted to effect the difference betweenthe output signal of the integrator and said seconD signal and a highgain amplifier adapted to transmit said difference amplified to theinput of the modulating member, the energising signal being constitutedby the output voltage of said modulating member.
 10. Feed deviceaccording to claim 8, in which said first signal is constituted, on eachturn of said rotary member, by a release pulse whose duration isproportional to the duration during which said rotary member effects arotation of a predetermined and constant angle and said second signal isconstituted by a continuous voltage whose value depends on the degree ofopening of the auxiliary throttling member, wherein the computing devicecomprises an oscillator adapted to deliver pulses with a frequencydependent on the value of said second signal and reading in and readingout means adapted, on each release pulse, on one hand, to count thenumber of pulses delivered by said oscillator during the duration of therelease pulse and, on the other hand, to read out with a given andconstant rythm the number of pulses delivered by said oscillator duringthe duration of the preceding release pulse, said reading in and readingout means providing, on each reading out a signal whose duration isproportional to the magnitude of the number of pulses read out and whichconstitutes the energising signal.
 11. Feed device according to claim 9,wherein the signal forming means comprises a flip flop with twoactuating inputs and two outputs, the first actuating input being fed bythe first signal, the second actuating input being fed by the outputvoltage of the modulating member, the first output being connected to aninput for bringing into action the modulating member and the secondoutput being adapted to furnish the energising signal, said energisingsignal being present on the second output when the flip flop is placedin a state whose start is actuated by the beginning of the rlease pulseand whose end is actuated by the end of the output voltage furnished bythe modulating member.
 12. Feed device according to claim 10, whereinthe reading in and reading out means comprise a summation means providedwith a first memory adapted to read in the number of pulses delivered bythe oscillator during the duration of a release pulse and a secondmemory adapted to record said number and to provide, under the action ofa generator of fixed frequency read-out pulses, a signal constituted bya succession of said same number of read-out pulses, the succession ofread-out pulses being applied to a decoding member adapted to supply anoutput voltage constituting the energising signal for a duration equalto that of said succession of read-out pulses.
 13. Feed device accordingto claim 12, wherein the readin and read-out means comprise a firstelectronic switch which is interposed between the first memory and theoscillator and which is actuated by the first signal so that the pulsesdelivered by the oscillator are only transmitted to the first memoryduring the duration of the release pulse, a second electronic switchwhich is interposed between the read-out pulse generator and the secondmemory and which is actuated by the first signal so that the pulsesdelivered by the readout pulse generator are transmitted to the secondmemory from the beginning of the release pulse of the first signal and aflip flop with two actuating inputs and two outputs, the first actuatinginput being supplied by the first signal, the second actuating inputbeing fed by the output voltage of the decoding member, the first outputbeing connected to the actuating input of the second electronic switchand a second output being adapted to supply the energising signal, saidenergising signal being present on the second output when the flip flopis placed in a state whose beginning is actuated by the beginning of therelease pulse and whose end is actuated by the end of the output voltageof the decoding member.
 14. Feed device according to claim 8, whereinthe energising signal is transmitted to the elecTromagnet through anelectronic switch which is actuated by comparison means adapted tocompare the duration of each energising signal to a corresponding fixedreference duration, so that said switch is closed and ensures thetransmission of energising signals to the electromagnet when theduration of said energising signals is greater than said referenceduration and said switch is open and does not transmit energisingsignals to the electromagnet when the duration of said signals is lessthan the reference duration.
 15. Fuel feed device according to claim 14,wherein said fixed reference duration is the duration of the energisingsignal when the internal combustion engine operates at slow speed.